If $x \circledcirc y = 7x+y$ and $x \otimes y = 3x-5y$, find $(5 \otimes 3) \circledcirc 0$.
Solution: First, find $5 \otimes 3$ $ 5 \otimes 3 = (3)(5)-(5)(3)$ $ \hphantom{5 \otimes 3} = 0$ Now, find $0 \circledcirc 0$ $ 0 \circledcirc 0 = (7)(0)$ $ \hphantom{0 \circledcirc 0} = 0$.